• Asian Journal of Atmospheric Environment
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• v.3 no.1
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• pp.42-51
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• 2009

Saturated n-dicarboxylic acids ($C_2-C_7$, $C_9$), unsaturated dicarboxylic acids (maleic, fumaric, phthalic acid), ketocarboxylic acids (pyruvic, glyoxylic acid), and dicarbonyls (glyoxal, methylglyoxal) were determined in size-segregated samples with a high-volume Andersen air sampler at a suburban site in Saitama, Japan, May 12-17 and July 24-27, 2007 and January 22-31, 2008. The seasonal average concentrations of these detected organic acids were 670 $ng/m^3$, accounting for about 4.4-5.7% (C/C) of water-soluble organic carbon (WSOC) and 2.3-3.6% (C/C) of organic carbon (OC). The most abundant species of dicarboxylic acids was oxalic acid, followed by malonic, phthalic, or succinic acids. Glyoxylic acid and methyglyoxal were most abundant ketocarboxylic acid and dicarbonyl, respectively. Seasonal differences, size-segregated concentrations, and the correlations of these acids with ambient temperatures, oxidants, elemental carbon (EC), OC, WSOC, and ionic components were also discussed in terms of their corresponding sources and possible secondary formation pathways. The results suggested that photochemical reactions contributed more to the formation of particulate organic acids in Saitama suburban areas than did direct emissions from anthropogenic and natural sources. However, direct emissions of vehicles were also important sources of several organic acids in particles, such as phthalic and adipic acids, especially in winter.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.1
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• pp.28-40
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• 2015

To investigate the seasonal variations of carbonaceous aerosol in Daejeon, OC (organic carbon), EC (elemental carbon) and WSOC (water soluble organic carbon) in $PM_{2.5}$ samples collected from March 2012 to February 2013 were analyzed. $PM_{2.5}$ concentrations were estimated by the sum of organic matter ($1.6{\times}OC$), EC, water-soluble ions ($Na^+$, $NH_4{^{+}}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, $SO_4{^{2-}}$, $NO_3{^{-}}$). The estimated $PM_{2.5}$ concentrations were relatively higher in winter ($29.50{\pm}12.04{\mu}g/m^3$) than those in summer ($13.72{\pm}6.92{\mu}g/m^3$). Carbonaceous aerosol ($1.6{\times}OC+EC$) was a significant portion (34~47%) of $PM_{2.5}$ in all season. The seasonally averaged OC and WSOC concentrations were relatively higher in winter ($6.57{\times}3.48{\mu}gC/m^3$ and $4.07{\pm}2.53{\mu}gC/m^3$ respectively), than those in summer ($3.07{\pm}0.8{\mu}gC/m^3$, $1.77{\pm}0.68{\mu}gC/m^3$, respectively). OC was correlated well with WSOC in all season, indicating that they have similar emission sources or formation processes. In summer, both OC and WSOC were weakly correlated with EC and also poorly correlated with a well-known biomass burning tracer, levoglucosan, while WSOC is highly correlated with SOC (secondary organic carbon) and $O_3$. The results suggest that carbonaceous aerosol in summer was highly influenced by secondary formation rather than primary emissions. In contrast, both OC and WSOC in winter were strongly correlated with EC and levoglucosan, indicating that carbonaceous aerosol in winter was closely related to primary source such as biomass burning. The contribution of biomass burning to $PM_{2.5}$ OC and EC, which was estimated using the levoglucosan to OC and EC ratios of potential biomass burning sources, was about $70{\pm}15%$ and $31{\pm}10%$, respectively, in winter. Results from this study clearly show that $PM_{2.5}$ OC has seasonally different chemical characteristics and origins.

• Korean Journal of Microbiology
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• v.6 no.3
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• pp.92-92
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• 1968

1) The aim of present investigation is to elucidate the relation of the balance of the production and decomposition of the fir litter. in Kwangnung plantation stands. 2) The decay constant, K, of litters was 0. 185 for the fir stand at Kwangnung. 3) The mode for the accumulation of organic carbon ($C_a$) is $c_a$= $610(1-e^{-0.185t})$), and for the decay of organic carbon (C) C = $610(1-e^{-0.185t})$. 4) The time required for the decay of half of the accumulated organic carbon in the fir stand is 3. 74 years and for 99% of elimination 27.02 years. 5) The litters of Abies holophylla killed by heat and washed with alcohol-benzol, with hot water, or with both alcohol-benzol and hot water were incubated after inoculated with suspension of firwood soil. Plate counts were made of fungi and bacteria from time to time. 6) Removal of the alcohol-benzol soluble substance stimulates at the beginning of the decay the growth of fungi and also of bacteria. 7) Removal of the water soluble fraction is detrimental to the growth of fungi in particular. 8) The distribution of soil microbial population is higher in both F and H horizon of the fir plantation soil in Kwangnung. However, the number of soil microorganisms decreases with the depth in forest soil.

• Korean Journal of Microbiology
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• v.6 no.3
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• pp.93-99
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• 1968

1) The aim of present investigation is to elucidate the relation of the balance of the production and decomposition of the fir litter. in Kwangnung plantation stands. 2) The decay constant, K, of litters was 0. 185 for the fir stand at Kwangnung. 3) The mode for the accumulation of organic carbon ($C_a$) is $c_a$= $610(1-e^{-0.185t})$), and for the decay of organic carbon (C) C = $610(1-e^{-0.185t})$. 4) The time required for the decay of half of the accumulated organic carbon in the fir stand is 3. 74 years and for 99% of elimination 27.02 years. 5) The litters of Abies holophylla killed by heat and washed with alcohol-benzol, with hot water, or with both alcohol-benzol and hot water were incubated after inoculated with suspension of firwood soil. Plate counts were made of fungi and bacteria from time to time. 6) Removal of the alcohol-benzol soluble substance stimulates at the beginning of the decay the growth of fungi and also of bacteria. 7) Removal of the water soluble fraction is detrimental to the growth of fungi in particular. 8) The distribution of soil microbial population is higher in both F and H horizon of the fir plantation soil in Kwangnung. However, the number of soil microorganisms decreases with the depth in forest soil.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.2
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• pp.5-10
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• 2018

This study was evaluated the characteristics of organic materials in the water source and the removal characteristics of organic materials by ultrafiltration including mixing and coagulation process. As a results of the study, it was found that the total organic carbon in the water source was mostly caused by the dissolved organic materials. As the specific ultraviolet absorbance value of the raw water was low, we found the soluble organic material has a high hydrophilic and low molecular material composition ratio. As a result of ultrafiltration experiment including mixing and coagulation process, the average removal rate of total organic carbon, dissolved organic carbon and ultraviolet absorbance at 254 were 37.9%, 30.3%, and 28.2%, respectively.

• Particle and aerosol research
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• v.9 no.3
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• pp.187-197
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• 2013

To understand the characteristics of organic aerosol(OA) at the background atmosphere of Korea, an observation of atmospheric PM10 was conducted at a Global Atmospheric Watch(GAW) station operated by the Korean Meteorological Administration at Anmyon Island during 2010. Various organic compounds were analyzed from 26 samples by using a gas chromatography-mass spectrometer. Water soluble organic carbon(WSOC) was also analyzed by using a total organic carbon(TOC) analyzer. Among 6 classes with 68 target compounds detected, the classes of n-alkanoic and alkenoic acids ($326.67{\pm}75.40ngm^{-3}$) and dicarboxylic acids ($323.74{\pm}361.89ngm^{-3}$) were found to be major compound classes in the atmosphere of Anmyon Island. Compared to the previous results reported for 2005 spring samples at Gosan site, the concentrations of organic compounds at Anmyon Island were 3-10 times higher than Gosan site due to the difference of location and sampling period. The concentrations of organic compounds were varied with the atmospheric conditions. Significant increase of the concentrations of dicarboxylic and carboxylic acids in the smog episode indicated that secondary oxidation of organic compounds was major factor to increase OA concentration during smog episode in the Anmyon Island. It was found that the compositions of the OA measured at Anmyon Island were dependent on the air parcel trajectories.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.3
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• pp.239-254
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• 2015

Little information on HUmic-Like Substances (HULIS) in ambient particulate matter has been reported yet in Korea. HULIS makes up a significant fraction of the water-soluble organic mass in the atmospheric aerosols and influence their water uptake properties. In this study 24-hr $PM_{2.5}$ samples were collected between December 2013 and October 2014 at an urban site in Gwangju and analyzed for organic carbon (OC), elemental carbon (EC), water-soluble OC (WSOC), HULIS, and ionic species, to investigate possible sources and formation processes of HULIS. HULIS was separated using solid phase extraction method and quantified by total organic carbon analyzer. During the study period, HULIS concentration ranged from 0.19 to $5.65{\mu}gC/m^3$ with an average of $1.83{\pm}1.22{\mu}gC/m^3$, accounting for on average 45% of the WSOC (12~ 73%), with higher in cold season than in warm season. Strong correlation of WSOC with HULIS ($R^2=0.91$) indicates their similar chemical characteristics. On the basis of the relationships between HULIS and a variety of chemical species (EC, $K^+$, $NO_3{^-}$, $SO_4{^{2-}}$, and oxalate), it was postulated that HULIS observed during summer and winter were likely attributed to secondary formation and primary emissions from biomass burning (BB) and traffics. Stronger correlation of HULIS with $K^+$, which is a BB tracer, in winter ($R^2=0.81$) than in summer ($R^2=0.66$), suggests more significant contribution of BB emissions in winter to the observed HULIS. It is interesting to note that BB emissions may also have an influence on the HULIS in summer, but further study using levoglucosan that is a unique organic marker of BB emissions is required during summer. Higher correlation between HULIS and oxalate, which is mainly formed through cloud processing and/or photochemical oxidation processes, was found in the summer ($R^2=0.76$) than in the winter ($R^2=0.63$), reflecting a high fraction of secondary organic aerosol in the summer.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.6
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• pp.633-641
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• 2016

Two identical Particle Into Liquid Samplers-Total Organic Carbon (PILS-TOC) were operated to measure fine particle Water Soluble Organic Carbon (WSOC) for one week on Feb. in 2016. The dual instrument operations provided validated WSOC concentrations to have a continuous WSOC measurement during the sample analysis period. Both PILS-TOC instruments were operated downstream of an carbon denuder to remove positive adsorption artifacts associated with semi-volatile organic compounds. Comparison of WSOC showed good agreement each other. The linear regression had a coefficient of determination ($r^2$) of 0.92 and a regression slope of 1.01 for the first period. The lower collection efficiency due to lower steam temperature is discussed. In addition, the potential primary source related to WSOC based on the comparison of black carbon (BC) concentrations is explained. The results of good agreement between two PILS-TOC measurements can provide the validation of WSOC cooperations and knowledge regarding the origins of WSOC and their behaviors.

• Membrane and Water Treatment
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• v.9 no.3
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• pp.181-188
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• 2018

A sidestream contains the filtrate or concentrate from the belt filter press, filter backwash and supernatant from sludge digesters. The sidestream flow, which heads back into the sewage treatment train, is about 1-3% less than the influent flow. However, the sidestream can increase the nutrient load since it contains high concentrations of phosphorus and nitrogen. In this study, the removal of PO4-P with organic matter characteristics and bacteriological changes during the sidestream treatment via ladle furnace (LF) slag was investigated. The sidestream used in this study consisted of 11-14% PO4-P and 3.2-3.6% soluble chemical oxygen demand in influent loading rates. LF slag, which had a relatively high $Ca^{2+}$ release compared to other slags, was used to remove $PO_4-P$ from the sidestream. The phosphate removal rates increased as the slag particle size decreased 19.1% (2.0-4.0 mm, 25.2% (1.0-2.0 mm) and 79.9% (0.5-1.0 mm). The removal rates of dissolved organic carbon, soluble chemical oxygen demand, color and aromatic organic matter ($UV_{254}$) were 17.6, 41.7, 90.2 and 77.3%, respectively. Fluorescence excitation-emission matrices and liquid chromatography-organic carbon detection demonstrated that the sidestream treatment via LF slag was effective in the removal of biopolymers. However, the removal of dissolved organic matter was not significant during the treatment. The intact bacterial biomass decreased from $1.64{\times}10^8cells/mL$ to $1.05{\times}10^8cells/mL$. The use of LF slag was effective for the removal of phosphate and the removal efficiency of phosphate was greater than 80% for up to 100 bed volumes.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.3
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• pp.337-346
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• 2011

24-hr integrated measurements of water-soluble organic carbon (WSOC) in PM2.5 were made between May 5 and September 25, 2010, on a six-day interval basis, at the Metropolitan Area Air Pollution Monitoring Supersite. A macro-porous XAD7HP resin was used to separate hydrophilic and hydrophobic WSOC. Compounds that penetrate the XAD7HP column are referred to hydrophilic WSOC, while those retained by the column are defined as hydrophobic WSOC. Laboratory calibrations using organic standards suggest that hydrophilic WSOC includes lowmolecular aliphatic dicarboxylic acids and carbonyls with less than 4 or 5 carbons, amines, and saccharides. While the hydrophobic WSOC is composed of compounds of aliphatic dicarboxylic acids with carbon numbers larger than 4~5, phenols, aromatic acids, cyclic acid, and humic-like Suwannee River fulvic acid. Over the entire study period, total WSOC accounted for on average 48% of OC, ranging from 32 to 65%, and hydrophilic WSOC accounted for on average 30.5% (9.3~66.7%) of the total WSOC. Based on the previous results, our measurement result suggests that significant amounts of hydrophobic WSOC during the study period were probably from primary combustion sources. However, on June 9 when 1-hr highest ozone concentration of 130 ppb was observed, WSOC to OC was 0.61, driven by increases in the hydrophilic WSOC. This result also suggests that processes, such as secondary organic aerosol formation, produce significant levels of hydrophilic WSOC compounds that add substantially to the fine particle fraction of the organic aerosol.